What would you do
I'm more curious how this works legally: with "normal" found objects,
you have to report it. If nobody picks it up within a year, you become the new owner.
With crypto, you basically find data, and the original owner can still have a backup. I've never seen a legal case about this.
Interesting thoughts. Not at all legal advice, just based on (my own) logic, I would say this is quite similar to finding a house with doors and windows wide open.
Even if you see gold coins glittering inside, you have no right to enter or take anything. You probably don't have any legal obligations to report such a finding (glittery goldcoins in an openly accessible unsecured house) but good manners (or call it moral standards) would suggest you should probably report it to police if you can't contact the owner directly.